ChapterGeneral formula of alkynes is CnH2n–2They are more acidic then alkene and alkane because they have sp hybridised carbon atom which is more elctronegative.Preparation PropertiesAlkynes resemble alkanes and alkenes in their physical properties. They share with those other hydrocarbons the properties of low density and low water-solubility. They are nonpolar and dissolve readily in typical organic solvents such as alkanes, and diethyl ether. Alkynes generally have slightly higher boiling points than the corresponding alkanes and alkenes due to more polar character. Normally they are colourless and odourless gas - acetylene is also colourless and odour
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ChapterTrihalogen DerivativesThe general formula of trihalogen derivative is CHX3These are also called HALOFORMS.Preparation(i) Haloform test is given by compounds having –COCH3 group.CH3COOH cannot give haloform test due to resonance and does not contain pure COCH3 group.C6H5COC6H5 Benzophenone does not give haloform test due to absence of –COCH3 group. 2-alkanol but cannot give haloform test because it is inert towards first step oxidation. Acetoacetic ester even though contains –COCH3 group but does not give haloform test due to active methylene group in the molec
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chapterGeneral formula of alkanes is Cn H2n+2They are also called paraffins (parum = Little + affinis = reactivity).They may have no bond polarity and does not contain in the molecule so known as saturated hydrocarbons.Preparation(i) From Grignard reagentRMgX alkyl magnesium halide (other examples of RMgX type molecules are RLi and R2Cd)This reaction is known as Zere wittinoff’s method for estimation of active hydrogen in the molecule. Active hydrogen is the one which is attached to a highly electronegative element. eg., N,O,S etc. Hydrogen attached to alkyl groups like —CH3, —C2H5 are never active due to less electronegativity of ‘C&rsquo
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ChapterGeneral formula of alkadienes is CnH2n–2Preparation of alkadienes(i) Dehydrogenation of butane(ii) Pyrolysis of Cyclo alkenes This reaction is known as Retro Diels – Alder reaction.(iii) Dehydration of diols(iv) Dehydrohalogenation by alc. KOH (v) From HCHOProperties of alkadienes(a) In 1,3- Butadiene all carbons are in sp2 hybridisation.(b) 1,3- Butadiene undergo resonance so that it undergo electrophilic addition reaction at both 1,2-and 1,4- position of molecule.(c) In Butadiene C2 – C3 bond length is 1.48 Å which is less than C – C bond length of ethane while C1–C2 or C3 – C4 bond length is 1.37 Å which is s
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ChapterMolecules that are attached to four different groups a, b, d and e are chiral.A tetrahedral carbon that is attached to four different group is known as a chiral centre, a chiral carbon atom, an asymmetric centre or an asymmetric carbon atom. Now a days a more modern term stereogenic centre is used.It we have to find, the presence of a stereogenic centre in a given molecule then we have to check if it is chiral. For example C-2 is stereogenic centre in 2-butanol. A stereogenic centre has four different groups. (a) In 2-chloropentane, C-2 satisfies this requirement. (b) None of the carbons in 3-bromopentane have four different substituents, and so none of i
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IntroductionThe existence of two or more compounds with same molecular formula but different properties (physical, chemical or both) is known as isomerism; and the compounds themselves are called isomers. The term was given by Berzelius. The difference in properties of two isomers is due to the difference in the arrangement of atoms within their molecules. Isomerism may be of two types:Structural isomerismWhen the isomers differ only in the arrangement of atoms or groups within the molecule, without any reference to space, these are known as structural isomersand the phenomenon asstructural isomerism.Thus the structural isomers have the same molecular formula, but p
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IntroductionBREAKING OF A COVALENT BOND Breaking of a covalent bond between two atoms can take place mainly in two alternative ways, viz. homolytic and heterolytic fissions depending upon the relative electronegativity of the two concerned atoms and medium of reaction.(i) Homolytic fissiontakes place when the two atoms (say A and B) are usually of similar electronegativity(ii) Heterolytic fissiontake place when the two atoms (A and B) are of different electronegativities. It may again take place in two different ways.(a)When A is more electronegative than B(b)When B is more electronegative than AIt is important to note that homolytic fission requires much less energ
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IntroductionIUPAC (Geneva System of Nomenclature)(i) Regular pattern of naming ide chain + alk + (-)ane or (=)ene or (=)yne + suffix of main functional group 1C Math 4C But 2C Eth 5C Pent 3C Prop 6C Hex (ii) Selection of LPCC ( longest possible carbon chain)The longest possible chain is numbered from one side to the other by Arabic numerals, the direction being so chosen as to given the lowest numbers possible to the side chains. When series of locants containing the same number of terms are compared term by term,
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Preparation(1) Hydrolysis of alkyl halides This reaction is useful only with reactants that do not undergo E2 elimination readily. It is really used for the synthesis of alcohols where alkyl halides are primary in nature. (2) Reaction of Grignard reagents with aldehydes and ketones A method that allows for alcohol preparation with formation of new carbon bonds. Primary, secondary, and tertiary alcohols can all be prepared and stepping up to two carbon atom also can takes place by the help of cyclic epoxides.
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IntroductionNucleophilic Substitution : Alkyl vs. AcylAs we have said, nucleophlic substitution takes place much more readily at an acyl carbon than at saturated carbon. Thus, toward nucleophilic attack acid chlorides are more reactive than alkyl chlorides, amides are more reactive than amines and esters are more reactive than ether.It is, of course, the carbonyl group that makes acyl compounds more reactive than alkyl compounds. Nucleophilic attack (SN2) on a tetrahedral alkyl carbon involves a badly crowded transition state containing pentavalent carbon ; a bond must be partly broken to permit the attachment of the nucleophile : Nucleophilic attack on a
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A solid is defined as that form of matter which possesses rigidity and due to which possesses a definite volume and a definite shape. – The solids can be classified into - (a) Amorphous solids (b) Crystalline solids The solids which do not have any definite shape geometrically are called AMORPHOUS (Morpha = form) solids. Infact these have a random and disordered arrangement of atoms. These solids are also called –super cooled liquids– and are without sharp melting points i.e., these have –short r
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Chemistry: Physical Chemistry ChapterIn mid, 17808 anatomist Luigi Galvani (Italy) was studying effects of atm. electric discharge. One day, in his garden, he fastened bross hooks b/w spinal cord of dissected frof and iron railing. He should that frog's leg began twitching wildly. He interpreted as animal electricity.In 1777, Alessandro volta repeated Galvani's famous experiments with decapitated frogs ole interpreted that twitches were due flowing of current b/w two dissimilar metals connected moist flesh of frog's leg.In 1801 volta awarded by Napolean a gold his discovery.Faraday achieved scientific prominence of his own for Istlaw of Electrochemistry,
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IntroductionNucleus the central core of an atom is held together by a short -range force called nucleus force, which is also a potential source of energy called Nuclear energy. in this unit we will first understand the phenomenon of radioactivity and its explanation using bindingenergy concept. we will later study about the radioactive decay characteristcs which hold emmense temperaturein age estimation of old rocks etc.Nuclear Characterstics:(1) Nuclear mass: The total mass of nucleus in the nucleus is called as nucleus mass.Nuclear mass =mass of proton + mass of neutron.(2) Radius of Nucleus: Radius of Nucleus holds the relationshipwhere R0= 1.1 x 1
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Neils Bohr gave forward his model of atom with answeres most of the flaws that Rutherford model had. This model introduced quantization principal and this model is regarded as first quantum mechanical model. We will explore in detail, this structure of atom. We will also look into X - ray formation which is a converse process of photoclectric effect and will examine Moreley's law in pantium. THE BOHR THEORY OF HYDROGE ATOM (AND HYDROGEN LIKE ATOM) Bohr gave following postulates for electron in hydrogen atom :- • An electron in an atom could resolve in certain stable orbits without the emission of radiant energy. • An elec
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Magnetics (Magnetic Field): Magnetic Force: The magnetic force ( on a charge q moving with velocity ina magnetic field is given both in magnetude and direction, by = q( x ) The Biot and Savart Law: Consider an infinitesinal element of length 'dl' of a wire carrying current I. The magnetre field d at P because of is given by the law: Magnetic field due to current in a straight line: (Secondary Information) at P due is = l = R cot, dl = - R cosec2d, r = R cosec
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